The Orlando Innamorato in English translation, Book I, Canto V, Stanzas 61-83 Notes
73. Boiardo never uses the word “sfinge”, but his monster is clearly meant to be one, and so I have added the name.
In Greek mythology there was only one sphinx, a monster which was guarded the roads to Thebes, put a riddle to passersby, and ate them if they couldn’t answer it. Hesiod says that Echidna lay with her son by Typhon, Orthus, a monstrous hound that was later Geryon’s watchdog, and the two of them produced the Sphinx and the Nemean Lion. Sophocles gives no description of the creature. Apollodorus states the Sphinx was sent by Hera, and was the daughter of Echidna and Typhon. She had the face of a woman, the breast, feet, and tail of a lion, and the wings of a bird. Her riddle about man is the only one she gives in Greek myth. Pausanias rationalizes the myth, claiming that Sphinx was the name of Oedipus’ sister, who seized a fortress near Thebes until Oedipus and his army slew her.
According to Pliny, sphinxes are a species that live in Ethiopia, have brown hair, and have two udders on their breasts. (VIII, xxx) That is the whole of his description, and he seems to have thought of the sphinx as a kind of monkey. Certainly Isidore of Seville lists the sphinx as a species of ape, and he is followed in this opinion by Western writers all the way down to Topsell.
81. Serpent’s hide. Probably meaning a dragon.
83. Orlando was made an honorary member of the Roman Senate out of gratitude after one of the numerous occasions when he saved the Eternal City from invading Saracens.